This is a Spanish form of eight syllable (Iambic Tetrameter) lines.
The rhyming scheme can vary in presentation, but only two consecutive lines may have the same rhyme scheme.
In the example below, Pat uses a.a.b.b.
a.

A flickering flame, on the wall
The sound of a, coyotes call
The desert winds, singing at night
Sandstorms dancing, in the moonlight
Embracing lovers, to befall

Pat Bibbs

Here is a lovely example by Sharon where she uses a rhyme scheme of; a.b.b.a.a. etc
.